Spindle Motor

ABSTRACT

A spindle motor is provided, the motor including a bearing assembly including an upper surface-opened cylindrical bearing housing and a bearing accommodated in the bearing housing and formed with a rotation shaft hole; a stator including a core coupled to a periphery of the bearing housing and a coil wound on the core; a rotation shaft inserted into the rotation shaft hole; a rotor including a disk-shaped yoke coupled to the rotation shaft and a magnet coupled to the yoke to face the core; and a suction magnet arranged at the yoke facing the core, wherein the bearing housing includes a body coupled to the core and a core fixture bent from the body to face the core, and the suction magnet is so arranged as to face the core fixture corresponding to an external side of a bent unit bent from the body for forming the core fixture.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit under 35 U.S.C. §119 of KoreanPatent Application No. 10-2010-0060418, filed Jun. 25, 2010, which ishereby incorporated by reference in its entirety.

BACKGROUND

1. Field of the Invention

The present disclosure relates to a spindle motor.

2. Description with the Related Art

Recently, an optical disk drive (ODD) has been developed that is capableof rotating a high capacity optical disk capable of recording or beingrecorded with data. The ODD includes a spindle motor rotating an opticaldisk at a high speed, and an optical pick-up module reading or recordingdata.

The spindle motor applied to the ODD includes a bearing housingincluding a bearing into which a rotation shaft is inserted, a corecoupled to a periphery of the bearing housing, a yoke coupled to therotation shaft, and a suction magnet mounted to the yoke to generate asuction force sucking the bearing housing.

The bearing housing functions to secure the rotation shaft to apredetermined position and to secure the core.

An upper surface of the bearing housing takes an outwardly-bent shapefor inhibiting the core secured at a periphery of the bearing housingfrom being separated, whereby the bent portion of the bearing housingtakes the shape of a curvature. The suction magnet according to aconventional spindle motor is disposed at a portion bent to have thecurvature in the bearing housing.

In a case the suction magnet is disposed at a portion bent to have thecurvature in the bearing housing, the spindle motor suffers from adisadvantage in that a suction force at the suction magnet and theportion having the curvature is unevenly formed to cause the rotationshaft to move along axis of the rotation shaft.

BRIEF SUMMARY

Exemplary embodiments of the present disclosure are to provide a spindlemotor in which a bearing housing is structurally improved to inhibit arotation shaft from moving along an axis of the rotation shaft byincreasing a suction force between the bearing housing and a suctionmagnet, and to enhance a rotational performance and rotationalstability.

Technical problems to be solved by the present disclosure are notrestricted to the above-mentioned description, and any other technicalproblems not mentioned so far will be clearly appreciated from thefollowing description by skilled in the art.

In one general aspect of the present disclosure, there is provided aspindle motor, the spindle motor comprising: a bearing assemblyincluding an upper surface-opened cylindrical bearing housing and abearing accommodated in the bearing housing and formed with a rotationshaft hole; a stator including a core coupled to a periphery of thebearing housing and a coil wound on the core; a rotation shaft insertedinto the rotation shaft hole; a rotor including a disk-shaped yokecoupled to the rotation shaft and a magnet coupled to the yoke to facethe core; and a suction magnet arranged at the yoke facing the core,wherein the bearing housing includes a body coupled to the core and acore fixture bent from the body to face the core, and the suction magnetis so arranged as to face the core fixture corresponding to an externalside of a bent unit bent from the body for forming the core fixture.

In another general aspect of the present disclosure, there is provided aspindle motor, the spindle motor including a bearing assembly, a stator,a rotor and a suction magnet, wherein the bearing assembly includes acore fixture bent to allow a core comprising the stator to be coupledand provided in the shape of a recess of a size corresponding to that ofthe core.

The spindle motor according to the present disclosure has anadvantageous effect in that a core is inhibited from separating byforming a core fixture at a bearing housing, and decrease or unevennessof suction force of a suction magnet between the suction magnet and thebearing housing caused by a curvature bent unit that is formed in thecourse of forming the core fixture can be inhibited by arranging thesuction magnet on the core fixture evenly formed at an external side ofthe curvature bent unit.

Additional advantages, objects, and features of the disclosure will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of thedisclosure. The objectives and other advantages of the disclosure may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

It is to be understood that both the foregoing general description andthe following detailed description of the present disclosure areexemplary and explanatory and are intended to provide furtherexplanation of the disclosure as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a spindle motor according to anexemplary embodiment of the present disclosure; and

FIG. 2 is an enlarged view of ‘A’ portion of FIG. 1.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments of the present disclosure aredescribed in detail with reference to the accompanying drawings. In thedrawings, sizes or shapes of constituent elements may be exaggerated forclarity and convenience.

Particular terms may be defined to describe the disclosure in the bestmode as known by the inventors. Accordingly, the meaning of specificterms or words used in the specification and the claims should not belimited to the literal or commonly employed sense, but should beconstrued in accordance with the spirit and scope of the disclosure. Thedefinitions of these terms therefore may be determined based on thecontents throughout the specification. The meaning will be clear fromthe context of the description. Like numbers refer to like elementsthroughout, and explanations that duplicate one another will be omitted.

As may be used herein, the terms “substantially” and “approximately”provide an industry-accepted tolerance for its corresponding term and/orrelativity between items. Such an industry-accepted tolerance rangesfrom less than one percent to ten percent and corresponds to, but is notlimited to, component values, angles, et cetera.

FIG. 1 is a cross-sectional view of a spindle motor according to anexemplary embodiment of the present disclosure, and FIG. 2 is apartially enlarged view of ‘A’ of FIG. 1.

Referring to FIGS. 1 and 2, a spindle motor (100) includes a bearingassembly (10) a stator (20), a rotation shaft (30), a rotor (40) and asuction magnet (50). The spindle motor (100) may further include a turntable (60), a center cone (70) and a base plate (15). The bearingassembly (10) includes a bearing housing (1) and a bearing (5). Thebearing housing (1) takes the shape of an upper surface-opened cylinder,and may include a metal.

The upper surface-opened cylindrical bearing housing (1) includes alateral plate (2), a floor plate (3), a core fixture (4) and a bent unit(4 a). The lateral plate of the bearing housing (1) may take the shapeof a cylinder, for example, and the floor plate (3) may be formed at abottom distal end of the lateral plate (2). In the present exemplaryembodiment, the lateral plate (2) and the floor plate (3) may be formedby a press work, for example.

An upper surface of the lateral plate (2) at the bearing housing (1) isbent to a direction facing an outside of the lateral plate (2), wherebythe core fixture (4) is formed at an upper end of the lateral plate (2).In the present exemplary embodiment, the core fixture (4) may besubstantially perpendicular to the lateral plate (2) of the bearinghousing, for example.

The bent unit (4 a) is formed in the shape of a band connecting thelateral plate (2) and the core fixture (4) by bending the lateral plate(2) of the bearing housing (1) to form the core fixture. The bent unit(4 a) takes the shape of a curvature, for example, and thecurvature-formed bent unit (4 a) is formed in the course of forming thecore fixture (4).

The core fixture (4) of the bearing housing (1) is perpendicularlyformed relative to the lateral plate (2), and the bent unit (4 a)connected to the core fixture (4) takes the shape of a curvature.

Meanwhile, a bottom surface meeting a periphery of the lateral plate (2)in the core fixture (4) is formed with a ring-shaped trench unit (4 b).The ring-shaped trench unit (4 b) inhibits an adhesive from overflowingoutside of the core fixture (4) when a core (described later) is fixedto the lateral plate (2) of the bearing housing (1) via the adhesive.

Furthermore, an upper surface of the core fixture (4) may be formed witha ring-shaped sill (4 c) formed at a predetermined depth. Thering-shaped sill (4 c) formed at the upper surface of the core fixture(4) restricts or reduces generation of chips when the bearing housing(1) is formed through a stamping process.

The bearing (5) is accommodated in an accommodation space formed at thebearing housing (1), and takes the shape of a rotation shaft hole-formedcylinder. In the present exemplary embodiment, the bearing (5) mayinclude an oil impregnated sintered bearing.

The bearing housing (1) of the bearing assembly (10) is coupled to abase plate (15). The base plate (15) is formed with a burring unit (17),which is in turn coupled to the lateral plate (2) of the bearing housing(1).

The stator (20) includes a core (21) and a coil (25). The core (21) isformed by stacking a plurality of iron pieces each having a thinthickness, and is centrally formed with a through hole coupled to thelateral plate (2) of the bearing housing (1). The coil (25) is wound onthe core (21) and a magnetic field is generated from the coil (25) as acurrent is applied to the coil (25) wound on the core (21).

An upper surface of the core (21) is brought into contact with the corefixture (4) bent from the lateral plate (2) of the bearing housing (1),whereby the core (21) is inhibited from separating from an upper surfaceof the lateral plate (2) at the bearing housing (1).

The rotation shaft (30) is rotatably inserted into a rotation shaft holeof the bearing (5) accommodated in the bearing housing (1).

The rotor (40) includes a yoke (45) and a magnet (48). The yoke (45)takes the shape of a bottom surface-opened cylinder. To be morespecific, the yoke (45) includes a yoke upper plate (42) and a yokelateral plate (44).

The yoke upper plate (42) takes the shape of a disk having a thinthickness, and is centrally formed with a yoke burring unit (43). Theyoke burring unit (43) is coupled to the rotation shaft (30), and theyoke upper plate (42) is rotated along with the rotation shaft (30) asthe rotation shaft (30) is coupled to the yoke burring unit (43).

The yoke lateral plate (44) is extended from an external edge of theyoke upper plate (42) to a direction facing a bottom side.

The magnet (48) is arranged at an inner lateral surface of the yokelateral plate (44) to face the core (21). The yoke (45) and the rotationshaft (30) are rotated by a magnetic field generated by the magnet (48)and a magnetic field generated from the coil (25) wound on the core(21).

The suction magnet (50) is arranged on a bottom surface of the yoke (45)facing the core (21) in the yoke (45), and takes the shape of a circularring, when viewed in a top plan view.

In the present exemplary embodiment, the arrangement of the suctionmagnet (50) is very important. The rotation shaft (30) may verticallymove along an axial direction of the rotation shaft (50) inside thebearing (5) according to arrangement of the suction magnet (50), and ina case the rotation shaft (30) vertically moves along the axialdirection of the rotation shaft (50), there may occur a data readingerror of an optical disk that rotates along with the rotation shaft(30).

The lift of the rotation shaft (30) may be generated when the suctionmagnet (50) is arranged at the bent unit (4 a) of the bearing housing(1). The lift is caused by decrease or unevenness of suction forceacting between the bearing housing (1) and the suction magnet (50) in acase the suction magnet (50) is arranged on the bent unit (4 a).

In the present exemplary embodiment, in order to inhibit the lift of therotation shaft (30), the suction magnet (50) is arranged at an innerlateral surface of the yoke upper plate (42) lest the suction magnet(50) should be overlapped with the bent unit (4 a). To be more specific,the suction magnet (50) is arrange at a position corresponding to thecore fixture (4) which is a planar surface arranged at an external sideof the bent unit (4 a), whereby the decrease or unevenness of suctionforce acting between the suction magnet (50) and the bearing housing (1)can be avoided.

Referring to FIG. 1, the turn table (60) on which an optical disk isaccommodated is arranged at an upper surface of the yoke upper plate(42). A though hole is formed at a rotation center of the turn table(60), and through hole of the turn table (60) is coupled by the rotationshaft (30). The turn table (6) is rotated along with the rotation shaft(30) as the through hole of the turn table (60) is coupled to therotation shaft (30).

The center cone (70) is inserted into the rotation shaft (30), and movesalong an axial direction of the rotation shaft (30). The center cone(70) matches a rotation center of the optical disk to that of therotation shaft (30).

As apparent from the foregoing, the spindle motor according to thepresent disclosure has an industrial applicability and advantageouseffect in that a core is inhibited from separating by forming a corefixture at a bearing housing, and decrease or unevenness of suctionforce of a suction magnet between the suction magnet and the bearinghousing caused by a curvature bent unit that is formed in the course offorming the core fixture can be inhibited by arranging the suctionmagnet on the core fixture evenly formed at an external side of thecurvature bent unit.

Any reference in this specification to “one embodiment,” “anembodiment,” “exemplary embodiment,” etc., means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the disclosure. Theappearances of such phrases in various places in the specification arenot necessarily all referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with any embodiment, it is submitted that it is within thepurview of one skilled in the art to affect such feature, structure, orcharacteristic in connection with others of the embodiments.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis invention. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

1. A spindle motor, comprising: a bearing assembly including an uppersurface-opened cylindrical bearing housing and a bearing accommodated inthe bearing housing and formed with a rotation shaft hole; a statorincluding a core coupled to a periphery of the bearing housing and acoil wound on the core; a rotation shaft inserted into the rotationshaft hole; a rotor including a disk-shaped yoke coupled to the rotationshaft and a magnet coupled to the yoke to face the core; and a suctionmagnet arranged at the yoke facing the core, wherein the bearing housingincludes a body coupled to the core and a core fixture bent from thebody to face the core, and the suction magnet is so arranged as to facethe core fixture corresponding to an external side of a bent unit bentfrom the body for forming the core fixture.
 2. The spindle motor ofclaim 1, wherein the core fixture takes the shape of a ring, and aring-shaped sill is formed at a predetermined depth on an upper surfacefacing a bottom surface contacting the core in the core fixture.
 3. Thespindle motor of claim 1, wherein the bottom surface of the core fixturecontacting the core is formed with a ring-shaped trench unit formed by arolling process to inhibit adhesive of the core from being leaked whenthe core is coupled to the body.
 4. The spindle motor of claim 1,wherein the bent unit is formed with a curvature.
 5. A spindle motor,including a bearing assembly, a stator, a rotor and a suction magnet,wherein the bearing assembly includes a core fixture bent to allow acore comprising the stator to be coupled and provided in the shape of arecess of a size corresponding to that of the core.
 6. The spindle motorof claim 5, wherein the bearing assembly includes an uppersurface-opened cylindrical bearing housing and a bearing accommodated inthe bearing housing and formed with a rotation shaft hole, and the corefixture is bent from the bearing housing to face the core.
 7. Thespindle motor of claim 6, wherein the rotor includes a rotation shaftinserted into the rotation shaft hole, a disk-shaped yoke coupled to therotation shaft and a magnet coupled to the yoke to face the core.
 8. Thespindle motor of claim 7, wherein the suction magnet is arranged at theyoke facing the core
 9. The spindle motor of claim 8, wherein thesuction magnet is arranged at a position facing the core fixture. 10.The spindle motor of claim 9, wherein the stator includes a core coupledto a periphery of the bearing housing and a coil wound on the core. 11.The spindle motor of claim 10, wherein the core fixture takes the shapeof a ring, and a ring-shaped sill is formed at a predetermined depth onan upper surface facing a bottom surface contacting the core in the corefixture.
 12. The spindle motor of claim 11, wherein the bottom surfaceof the core fixture contacting the core is formed with a ring-shapedtrench unit formed by a rolling process to inhibit adhesive of the corefrom being leaked when the core is coupled to the body.
 13. The spindlemotor of claim 12, wherein the bent unit is formed with a curvaturehaving a predetermined radius of curvature.